A word from Kristine, the 'Lego Batman and Lego Emmet' costume creator:

These costumes were made for my two sons age 4 and 5 by myself. It took for me three weeks to make them. The costumes are made of cardboard and heads and hands are made of styrofoam. Painted over with ordinary arts and crafts paint. They came out very good but unfortunately it rained on Halloween and paint started to run off but the boys had great fun and everyone loved their costumes...